1. Field of the Invention
This invention relates generally to sensors utilizing electromagnetic energy for detecting the passage of substances through a chamber, and more particularly to such sensors in which said electromagnetic energy is non-resonant.
2. Description of the Related Art
Sensors which use electromagnetic energy for detecting the passage of a substance through a chamber are well known in the art and have found applications in a number of industries. For example, in the agricultural industry, electromagnetic sensors have been used for monitoring seed planting operations as disclosed in U.S. Pat. No. 4,246,469 to Merlo, and for monitoring crop moisture as disclosed in U.S. Pat. No. 5,708,366 to Nelson. In the petroleum industry, sensors using electromagnetic energy have been used for determining solid-to-liquid ratios in a flowing petroleum stream as disclosed in U.S. Pat. No. 5,644,244 to Marrelli et al.
Unfortunately, the inventions disclosed in these patents fail to solve the need of providing a single sensor that can be used for detecting the presence, flow-rate, and/or volume of various substances, whether the substance being measured is a solid, a liquid, or a gaseous material such that only one sensor is needed for all the monitoring needs of a user. Nor do these sensors provide for both quantitative and qualitative detection of substances. Thus, those concerned with these and other deficiencies recognize the need for an improved electromagnetic energy sensor.